Implementation Details ---------------------- This page describes how our lab implemented the procedures required by the official protocol for the RRR. It also describes and justifies any additions to or departures from that protocol. You can view the official protocol and the main project page for this RRR using these links: - Official Protocol: [https://osf.io/ypd78/][1] - Main RRR project page: [https://osf.io/scu2f/][2] ---------- #### Experimenters #### - Dorothee Mischkowski, M.Sc. Psychology, PhD student (3rd year) at Göttingen University with a research focus on cooperation behavior and social value orientation - Prof. Andreas Glöckner, head of department for Psychological Assessment, Judgment and Decision Making at Göttingen University and senior research fellow at the Max-Planck Insitute for Research on Collective Goods, Bonn. - Data collection will be conducted by experienced research assistants (mainly undergraduate students), all German native speakers and familiar with conducting experiments on social dilemmas. They are overseen by Dorothee Mischkowski. ---------- #### Setting/Lab/Equipment #### Data collection will take place in a computer lab with 12 cubicles, so that an anonymous setting of three Public Goods Games in parallel is assured. Participants have access to a Dell laptop with a 13" inch screen. Participants are positioned so that they cannot see each other or the computers used by other participants. - Lab Picture [https://www.dropbox.com/s/z9d11vxzb8pcx3w/Lab_Goettingen_III.jpg?dl=0][3] - Cubicle Picture [https://www.dropbox.com/s/fatcad36hj9vpc4/Lab_Goettingen_Laptop.jpg?dl=0][4] ---------- #### Sample, subjects, and randomization #### **Target sample size:** Data of a total sample of 204 participants is going to be collected. **Target sample demographics:** - Data consists of a classic student sample, recruited from a broad student data base; also including, but not limited to Psychology students - A mean age of 24-25 years with approx. 60-70% female participants is expected. The sample includes mainly German participants - Participants will be compensated with a participation fee (5,-Euro) and a bonus according to their outcome in the Public Goods Game (PGG) and the SVO Slider Measure (about 3€, see below at additional measures for further information). The endowment for the PGG will consist of 4,-Euro. **Minimum sample size after exclusions:** The minimum sample size will consist of 80 participants in each condition, resulting in a minimal total sample size of 160. A total sample size of N = 204 (102 per condition) is aimed. **Stopping rule(s):** Participants are invited via the database of the department. Persons that already took part in social dilemma experiments are not invited to the sessions. We will schedule groups of 12 participants with the goal of conducting 17 testing sessions, yielding 204 participants (102 in each condition). After completing those sessions, we will check for exclusions. If, after exclusions, we have usable data from at least 80 participants in each condition, we will stop data collection. If we have fewer than 80 in either condition, we will test additional sessions of 12 participants until we have usable data from at least 80 participants in each condition. **Randomization to conditions:** Participants will be randomly assigned to conditions by the provided Qualtrics script. **Blinding to conditions:** No communication is allowed among participants during the session. Participants are debriefed at the end of the session about the study goal. In addition, they are asked not to share the debriefing information with other potential partipants. No written debriefing is distributed that could lead to common knowledge about the two conditions. **Exclusion rules:** We will be using the exclusion rules required by the official protocol. **Procedures for handling testing sessions for which the number of participants is not a multiple of 4:** We will try to have another experiment ready that doesn't require group interactions. Generally, we will overbook the sessions with one extra participant as the show-up rate in our lab does not always reach 100%. In case we have a number of participants that is not a multiple of 4 and no further experiment at hand, we will provide a show up fee of 3,-Euro to participants, explain the situation and invite them to another session (with a guaranteed participation opportunity). ---------- #### Software/Code #### We confirm that we will be using the provided materials, including the Qualtrics scripts. For this purpose, a Qualtrics license will be bought. As data collection will take place in Germany, a forward-backward translation of the instructions is necessary and coordinated with the other two participating German labs, so that everyone will use the same instructions. ---------- #### Differences from the official protocol #### Additional Measure - We would like to add the continuous measurement of Social Value Orientation (SVO) after the Public Goods Game by taking the 15 items SVO Slider Measure by Murphy, Ackermann, & Handgraaf (2011). SVO represents a continuous measure of social preferences, “defined in terms of the weights people assign to their own and others’ outcomes in situations of interdependence” (Balliet, Parks, & Joireman, 2009, p.533). In a series of 15 decomposed games, participants are matched in pairs and allocate different amounts of money to themselves and the other player. - The influence of social value orientation on cooperation behavior in strategic interactions has extensively been shown (e.g. Van Lange, 1999). In a meta-analysis, Balliet et al. (2009) find a significant effect on cooperation behavior of r = .30. - In earlier replication trials, Mischkowski & Glöckner (submitted) identify SVO as a moderator of the spontaneous cooperation effect in that the spontaenous cooperation effect is only valid for prosocials. - We assure that the SVO measure does not inflate the results of the PGG: The SVO measurement will take place after the PGG. Additionally, both games - SVO Slider and PGG - will be incentivized (instead of randomly picking one). The SVO Slider has an expected value of 3,-Euro (min. 2,-Euro, max. 3.40 Euro). - Participants are informed holistically prior to the study, so they know that they will take part in a study that takes roughly 45 minutes and offers them up to 18,40€ (including the 5€ participation fee), but they don’t know that the study is divided into two parts and that their payoff consists of the sum of these two parts. This way, they shouldn’t think differently about their funds during the RRR study. - The SVO Slider measure has been forward-backward translated for earlier studies; the English version can be found here [http://vlab.ethz.ch/svo/SVO_Slider/SVO_Slider_paper_based_measures_files/SVO_slider_va_p12_blank.pdf][5] - To match the SVO Slider data with the Qualtrics data, participants generate a code (a combination of letters and numbers) in both programs. For this reason, an item at the very end of the Qualtrics file is added, that allows an anonymous matching of both data files. [1]: https://osf.io/ypd78/ [2]: https://osf.io/scu2f/ [3]: https://www.dropbox.com/s/z9d11vxzb8pcx3w/Lab_Goettingen_III.jpg?dl=0 [4]: https://www.dropbox.com/s/fatcad36hj9vpc4/Lab_Goettingen_Laptop.jpg?dl=0 [5]: http://vlab.ethz.ch/svo/SVO_Slider/SVO_Slider_paper_based_measures_files/SVO_slider_va_p12_blank.pdf